Recent results have shown that during inflammatory processes, myeloid cells exhibit extensive plasticity of their phenotype in response to numerous stimuli. This characteristic directly affects lymphocyte polarization and activity and is controlled by changes both at transcriptional and translational level. This previously unanticipated degree of epigenetic control of myeloid cells, which affects both innate and adaptive immune responses, is likely to impact several aspects of future studies in human immunology and to inform on immunotherapeutic strategies. This Keystone Symposia meeting will cover topical aspects of basic myeloid cell biology and their interface with clinical research, bringing together scientists and clinicians working on all the subtypes of myeloid cells in health and disease, from neutrophils and monocytes to macrophages and dendritic cells. The speakers will provide an overview of myeloid cell ontogeny, role of different myeloid cell subtypes in the modulation of innate and adaptive immunity, antigen capture and presentation, mobilization from the bone marrow and trafficking during inflammatory responses. The symposium will touch on multiple areas central to contemporary immunology and cell biology, including the interface between innate and adaptive immunity, as well as the mechanisms enforcing immunosuppression in cancer and infectious diseases.